In any field of science, particularly applied sciences, The Literature does not come out until long after the science has been theorized, practiced, and preached. Shamans were “curing” people long before Fleming discovered penicillin. We can only hope experiments validate that which we have conjured up in our measly brains or learned from the elders, but we are seldom this lucky, as is the case for shamans healing cancer by aligning chakras or whatever it is they do. Resistance training (RT) has been around in its modern form, with barbells and such, for the better part of a century, perhaps a little longer. However, the dumbbell and similar items have been around for thousands of years and physical training of some form is likely prehistoric. In comparison, The Literature is in its infancy. Old habits die hard, but sooner or later we have to burn off the deadwood.
Though The Literature is still young and growing, it has much to teach us. If my Dear Reader considers himself a trainer/coach/prophet or merely a Student of the Game, he should spend the time necessary to go through this. It will only make him more knowledgeable and well-reasoned. The intention of this article is not to ruffle feathers, although I won’t pretend I don’t enjoy doing it whenever I get the chance. I want everybody’s training to be optimized, and I certainly would like the trainer/coach golden retrievers to be replaced with Men Who Understand Science. The Literature should act as the wind necessary to guide our sails. If we do not wrestle with the science we have no idea which way the wind is blowing. However, this is a lot of information and if the Reader is relatively new it may seem overwhelming.
This will be a Deep Dive into the hypertrophy literature and how we should go about accumulating hypertrophy. I say accumulate because hypertrophy is a process, not a fixed goal one can achieve. Resistance training is our best tool for inducing hypertrophy along with being in a caloric surplus, and this post will be concerned specifically with the training prescription necessary to maximize G A I N S. As the article continues it will get further in-depth and we shall continue our descent down the rabbit hole. I thought about trying to shorten it by including multiple studies for a single conclusion, explaining less, et cetera. But, the less thorough this is the more room for interpretation left to the Reader. That is not my goal for this article. I want to remove any chance of an arrow piercing the armor. By the end, my Dear Reader will be hit with a summary and some pragmatic guidelines. Come along with me as I venture into the voluminous depths of The Literature.
The Import Definitions™
Volume – sets multiplied by reps, e.g. 5 sets of 5 reps would be 25 reps of volume.
Volume Load (VL) or Tonnage – resistance multiplied by sets and reps, e.g. 5 sets of 5 reps with 225 lb would be 5625 lb of tonnage or VL.
Cross-Sectional Area (CSA) – the area of the cross-section of a muscle perpendicular to its fibers.
Repetition Maximum (RM) – “rep max” or the maximum amount of weight that can be lifted for a certain number of repetitions. Usually written as 1RM, 5RM, 10RM, et cetera.
Intensity – the percentage of one’s RM, often written as “60%1RM”, which would be 60 percent of a lifter’s 1RM weight. If a lifter can squat 200 lb for a maximum of five reps, 80%5RM would be 160 lb.
Whether the subjects in the studies are trained is quite relevant so I will bold and italicize every case where it is known. I will provide links to every study and the bibliography will be at the bottom. GET SOME COFFEE.
VOLUME – Minimum Effective Dose?
In our world of training, the MED would be the smallest possible stress we could undergo in order to induce an adaptation. This is popular, especially with the Tim Ferriss types, as he’s built a multi-million dollar empire on this exact ideology. Although, at average height, I think the Reader would rather lift like Dan Green than Tim Ferriss. But how? Let’s look at the data.
What is needed to produce a hypertrophic response from training? While it is certainly possible that an untrained lifter could benefit from doing a single set to volitional end or failure, how long would that last as a viable stimulus that would call for an adaptation? Is it even possible for a trained person who’s been lifting seriously for, say, six-plus months to find a single set to be an overload event? The MED has obvious value, but let us see what the data tell us. All four of these entries were compiled in Schoenfeld and Grgic‘s work, but they showed:
- 3 sets v. 1 set – 36 untrained men performed either three sets of leg extensions or one set of leg extensions. While the evidence was not conclusive, the first group’s thigh cross-sectional area grew 6.8 percent v. the second group’s 3.1 percent. Not statistically significant but practically so, as the group utilizing multiple sets had a 119 percent greater hypertrophic response. We would expect a large cohort of untrained men to respond to a new training stimulus no matter what it is since almost anything will disrupt homeostasis. However, even in untrained men, three sets appeared more valuable than just one.
- 4 v. 2 v. 1 – three groups of resistance-trained men did one, two, or four sets of leg extensions and growth in the cross-sectional area of the quadriceps hit 6.3, 4.6, and 12.3 percent, respectively. Again, while not statistically significant, meaningful for us. One set and two sets seemed hardly different, even a bit of a drop in the average response for the latter group, but the group who did four sets saw 95 percent more growth than the first group.
- More is better – eight total studies were included in a meta-analysis done by Krieger to understand whether a single set or multiple sets is more beneficial to hypertrophy. Across the board, unsurprisingly, multiple sets were better.
- More is better, ten plus – 15 studies were included in a meta-analysis to look at the number of sets performed per muscle group per week (<5, 5-9, 10+) and they found that more is better. The gains in hypertrophy were 5.4, 6.6, and 9.8 percent, respectively.
Let me dig into the aforementioned meta-analysis of eight studies done by Krieger. He found a 40 percent increase in hypertrophic effect sizes in the studies when multiple sets (2-3) were compared with single sets. Moreover, the effect sizes grew again when 4-6 sets were studied. If I were to borrow a mathematical idea from Mr. Science, Greg Nuckols, and calculate a parabolic line of best fit for the effect sizes, I would be able to visualize a unitless “hypertrophic effect” (y-axis) per set (x-axis). Essentially, how valuable each consecutive set is to our G A I N S. In addition, it will provide us with an idea of where a point of diminishing returns may pop into the equation for lifters. All of this would obviously be largely dependent on training history and efficacy, but it’s a good illustration.
Krieger’s work would also jibe with the meta-analysis done by Peterson et al., as they combined a staggering 177 studies with 1,803 effect sizes to understand how untrained lifters, recreationally trained lifters, and athletes responded to training volume for strength gains.
In the work of Peterson et al. we see that upwards of eight or more sets per training session can be required for an athlete, somebody with an extensive training history, to maximize strength gains. In untrained folks, as low as 60 percent of 1RM can be used with only four working sets to maximize strength three days per week, but I already discussed why it is impossible to get an accurate 1RM in untrained lifters, as they do not possess the neuromuscular efficiency or skill to perform the task of a maximum-effort lift and they can get stronger every time they workout for several consecutive weeks. Untrained lifters are sent to Starting Strength: Basic Barbell Training. Recreationally trained lifters responded best to a mean training intensity of 80%1RM with four sets, only two days per week. Athletes, on the other hand, needed a mean of eight sets per muscle group twice per week to maximize strength gains. So, there exists a strong correlation between increasing volume and maximizing hypertrophic gains, but also for maximizing strength gains.
Since we thoroughly understand homo sapiens and their tendency to wither and die from too much stress, we can intuit that an upper threshold of training volume must exist. We will hit a point of diminishing returns where the effort-to-benefit ratio begins to increase drastically. That is known in The Biz as a “waste of time”. Soon after that, we would hit a point at which increasing volume any further would result in a detriment to our training, e.g. crippling soreness, increased risk of injury, unhelpful fatigue, bad taste in music, et cetera.
One study by Amirthalingam et al. tested German Volume Training (GVT), often called the 10-set method, against a more prototypical hypertrophy program involving five sets. The men involved were trained with at least one year of experience. Instead of typing it all out for the Reader, the two protocols were:
As we can see, the first two exercises were either a GVT prescription of 10 sets of 10 reps (that’s going to be a yikes for me, dawg) or five sets of 10 reps. Both groups, however, performed assistance work and at the same intensity/volume. This was done to comply further with the philosophy of the split routine implemented by most bodybuilding/hypertrophy-focused lifters.
The 5-set group gained 71 percent more total body mass and 42 percent lean body mass (LBM) over the GVT group. Lean tissue growth in the arms and trunk favored the 5-set group as well. The 5-set group saw a 72 percent greater increase in 1RM leg press strength, a 140 percent greater increase in 1RM bench strength, and a 236 percent greater increase in 1RM lat pull-down strength. The only GVT-favored outcome was muscle thickness in the triceps. This gives us a clear warning about the potential for 31 working sets per muscle group versus 21 working sets per muscle group per week. There is an obvious point of diminishing returns, although an increase in strength and LBM was still observed in the GVT group, so they certainly were not regressing. However, it’s unclear how long they would be able to withstand this level of volume.
The data show that the Minumum Effective Dose has Minumum Effective Value unless the lifter is untrained. It is clear that we need more stress and specifically, more volume rather than less. We especially need more volume if we are looking to maximize hypertrophy, and the battle against Father Time is always an uphill fight (unless the Reader is LeBron James. If he is LeBron, contact me so we can fix that hideous squat form, I will fly to LA yesterday.). As we make more progress G A I N S become more marginal and we will have to turn over every stone in order to keep moving forward. More sets are better than fewer sets, but how many repetitions should we use?
In this study by Morton et al., we see forty-nine trained young men perform full-body workouts three times per week for 12 weeks using either 30-50%1RM for 20-25 reps per set or 75-90%1RM for 8-12 reps per set. There were no significant differences in increase between the groups in acute changes in systemic hormone concentrations, skeletal muscle biopsies, strength testing, and dual-energy X-ray absorptiometry scans. The only significant difference was in bench press strength, the group with the high-load, low-rep prescription improved significantly more (HR, 9 ± 1, vs. LR, 14 ± 1 kg, P = 0.012).
In this study by Campos et al., four groups of untrained men went through an eight-week training protocol. Group one (Low Rep, n=9) performed three to five reps for four sets of each exercise with three-minute rest intervals. Group two (Int Rep, n=11) performed 9-11RM (Never Forget) for three sets with two-minute rest intervals. Group three (High Rep, n=7) performed 20-28RM for two sets with one-minute rest intervals. The fourth group was a non-exercising control (Con, n=5). Three exercises (leg press, squat, and knee extension) were performed two days per week for the first four weeks and three days per week for the final four weeks.
“Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group.” This is not a surprise, as merely practicing 20-28RM consistently would make one better at performing high-rep maximal sets. We also know that strength adaptations become more specific the longer we train and there are skills involved in performing a one-rep max that one does not get if they consistently train in moderate to high-rep schemes. Vice versa for high-rep max sets and training in low-rep schemes.
“All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups.” This is actually quite surprising. For a group of untrained men, the High Rep prescription should have forced some form of growth because untrained subjects usually grow no matter what they do, this is the nature of going from untrained to trained. However, the high-rep scheme proved antithetical to hypertrophic gains in this case.
A study by Klemp et al. tested two groups of trained men with two nearly equal volume prescriptions for daily undulating periodization strategies over eight weeks. The first group (DUPHR, n=8) performed 4×12 at 60%1RM on day 1, 4×10 at 65%1RM on day 2, and 5×8 at 70%1RM on day 3 for the squat and bench press exercises only. The second group (DUPLR, n=8) performed 8×6 at 75%1RM on day 1, 9×4 at 80%1RM on day 2, and 10×2 at 85%1RM on day 3 for the same two exercises. DUPHR, the high-rep group, performed 128 working reps of volume against DUPLR’s 104 reps. However, DUPLR, the low-rep group, had a 15.24 percent average increase in pec cross-sectional area (CSA), and 11.23 percent average increase in quad CSA. DUPHR had a 12.72 percent average increase in pec CSA and 11.15 percent average increase in quad CSA. There was not a significant increase in hypertrophy from performing higher reps and the results slightly favored the DUPLR group.
Lastly, let us understand the meta-analysis by Schoenfeld et al. on Strength and Hypertrophy Adaptations Between Low- Vs. High-Load Resistance Training. They found 21 studies that met their criteria and concluded that the spectrum of high-load (low-rep) down to low-load (high-rep) provided similar hypertrophic effects, but the results slightly favored high-loads. Far from statistically significant, they were unable to say one is more beneficial than the other. They were, unsurprisingly, able to definitively call high-load training significantly more beneficial for strength gains, particularly 1RM performances.
Moreover, they found a tendency for load-specific outcomes in muscle fiber growth. The higher the load the more type II fibers grow and the lower the load the more type I fibers grow. This is not a shocking discovery, as we know what this about the fibers:
Since we know this about muscle fibers, it would follow that strength training, particularly short, heavy strength training, would predominantly require the use of type II fibers. The opposite would, therefore, be true for slow, lighter strength training that is to be held out for up to several minutes per set. To best Grow Large and take up all the space in the booth at Applebee’s, rep schemes of all flavors should find a spot in the lifter’s training. However, since type II fibers are the biggest and baddest, training should still center around high-loads.
If high repetitions, 15 or more, require us to take plates off the bar and sacrifice strength gains, but low-to-moderate repetitions, 1-12, allow us to get mightily strong and influence hypertrophy as much as the former, why should we spend a considerable amount of time with high reps? It seems to me that we shall only look North of 15 when we really want The Pump™ or happen to remember that we even have type I fibers. Well, now we know how many reps we need to fall in love with, but is failure better than a volitional finish to a set? The short answer is no, but I am not one for such a brief response.
Failure v. Volitional Sets
This study by Nobrega et al. showed in thirty-two untrained men that high-intensity and low-intensity sets done not to failure but stopped volitionally had the same effect on muscle mass, strength, and pennation angle as high and low-intensity sets done to failure. This could imply that sets taken to failure are not necessarily more beneficial to sets ended with reps left in the tank, i.e. sets at an RPE of 7-9.
This study by Sampson and Groeller assessed a more specific response in untrained men, as they tested non-failure rapid shortening (RS: 2s eccentric, rapid concentric), non-failure stretch-shortening (SSC: rapid eccentric, rapid concentric), and failure control (C: 2s eccentric, 2s concentric) 3 times per week with 85% of 1RM in 28 men. They were studying 1RM, maximal voluntary contraction (MVC), muscle cross-sectional area (CSA), and muscle activation (EMG(RMS)) of the agonist (prime movers), antagonist (opposing muscles), and stabilizer muscles before and after the 12-week program.
The average number of reps performed in RS was 4.1, SSC was 4.2, and C was 6.1, so it appears the group working to failure underwent more volume on average. Every parameter (MVC, CSA, EMG) improved, but no significant difference was detected amongst the groups, implying that lifting to failure doesn’t provide any significant evidence for better hypertrophic outcomes, even if the volume was slightly higher.
For what it is worth, this study by Prestes et al. suggests that Rest-Pause sets may show a significant increase in thigh hypertrophy and localized muscle endurance in the leg press over traditional multiple sets with a normal rest interval. The muscle endurance improvement would imply that practicing reps with very little rest made the subjects better at performing reps with little or no rest, which would certainly comply with the Specificity of Adaptation to Imposed Demand (SAID) principle and the one I just made up, called the Duh principle. I think this rest-pause training strategy may be useful to employ every now and then, perhaps during relatively low-stress volume work at the end of a session. My tactic of choice for volume that follows a Rest-Pause prescription are Myo-Reps.
While we are on the subject of strange reps, a study done by Masahiro et al. showed that a partial range of motion (ROM) program showed significantly better hypertrophic responses from an increase in intramuscular hypoxia than a full ROM program. This suggests that partial ROM training and exercises should hold a place in our training. Block benches, rack pulls, halting deadlifts, that kind of thing. We already know they are excellent for building strength, but they seem to also be quite beneficial for hypertrophy.
Anyway, many of the studies listed in these paragraphs utilize failure because of the subjectivity involved in stopping a set volitionally. This renders it somewhat tough to find many studies that directly pit failure against a volitional end, but the couple cited above give us an idea that failure does not seem to represent any unique characteristics that the latter does not. To me, failure is a great way to accumulate unnecessary fatigue, increase our risk of injury (especially in barbell exercises and heavy compound movements), and require the regular use of a spotter. Some of us don’t have any friends to goad into holding our elbows while we press dumbbells. We have to use the old-fashioned method of safety: prayer.
Now we know that we need many working sets of volume per week, at least 10 per movement/muscle group, and we also know that we need to cycle our rep schemes throughout the 1-12 range. But wait, how long should we rest between sets? The bodybuilders might get upset with me over this one, but if they take three deep breaths and attempt objectivity they will find the next segment to be good news.
A study by Schoenfeld et al. tested twenty-one trained male volunteers for 1RM in the bench press and back squat, muscle endurance at 50 percent of 1RM to failure, and muscle thickness of the elbow flexors, triceps brachii, and quadriceps femoris. Both groups were prescribed three sets of 12 reps for seven exercises for three full-body workouts per week. The only difference was one group (SHORT – 11 subjects) was allowed a one-minute rest interval while the other group (LONG – 10 subjects) was allowed three-minute rest intervals. As expected, the 1RM tests for the bench press and back squat showed significantly more improvement in the LONG group than in SHORT. However, contrary to what we would normally expect, the LONG group showed greater hypertrophic responses as well. The increase in anterior thigh CSA was significantly better in the LONG group, and the triceps brachii improvements were trending in the same direction. The difference in biceps brachii CSA increases did not show statistical significance, but the effect size suggests that the LONG group’s biceps responded more than the SHORT group’s (.39 and .18, respectively) and may have shown a bigger discrepancy had the study continued for several more weeks.
This study by Buresh et al. tested twelve untrained males for changes in hormone response, strength, arm cross-sectional area (CSA), thigh muscular cross-sectional area (MCSA), and body composition during a 10-week training period and used either one or 2.5 minutes of rest between sets. The long-rest group saw a significantly greater increase in arm CSA over the short-rest group. This is likely due to the fact that the long-rest group was able to perform many more repetitions per set, on average, than the short-rest group. The 1-minute rest interval elicited a greater hormonal effect than the 2.5-minute interval, but this vanished by week 5. This means that as the lifter became more trained, the hormonal effects, assumed to increase anabolism and hypertrophic outcomes, were not significantly different.
Another study, this one by Ahtiainen et al., took two groups of trained men through six months worth of training to test basal hormonal concentrations of serum total testosterone (T), free testosterone (FT), and cortisol (C), maximal isometric strength of the leg extensors, right leg one-repetition maximum (1RM), dietary analysis, and muscle cross-sectional area (CSA) of the quadriceps femoris by magnetic resonance imaging (MRI) were measured at months zero, three, and six. The first group (LONG – five-minute rest intervals) was compared to the second group (SHORT – two-minute rest intervals) in order to see the effects of longer rest intervals. They found very little. The LONG group used higher intensities so they trained with heavier weights consistently, but the muscle size, hormone levels, and strength performances improved to a virtually identical degree.
I think the big takeaway from this is, as in our previous study, resting only one minute is far from ideal. We would be wise to utilize rest intervals between two and five minutes. This is obviously a big range, but let me talk through it. If a 4 or 5-minute rest interval would allow us to recover more than a 2-minute interval, it would follow that we would be able to safely execute more reps and increase our volume and tonnage for each exercise and workout. This would result in, especially over several months of training, a vast improvement in accumulated training workload. Furthermore, if the two-minute interval does not improve our workout in any tangible metric outside of The Pump™, why would we shortchange our improvements in strength, volume, and work capacity by doing less work?
A meta-analysis from de Salles et al. looked at the relationship between inter-set rest intervals and training outcomes in 35 studies. The acute effects are exactly what we’d assume.
As I predicted (because my IQ is above 30), the longer the lifter rested the more reps, on average, he/she was able to execute throughout each study. The Reader can get out a sheet of paper and check my math, but I’m quite sure of the fact that when a bigger number is added to a bigger number it creates a bigger sum than if the numbers were to be, well, smaller. Even at the low intensities, 50%1RM, there was a massive difference between one, two, and three-minute rest intervals.
For Willardson and Burkett’s second study above, I’m going to plug in 200 lb as the average bench press 1RM for the subjects. This will illustrate the amount of work we are missing if we utilize short rest intervals. The numbered list represents the duration of the rest interval. The volume and tonnage were:
- 80% (17.8 reps for 2848 lb) — 50% (58.9 reps for 5890 lb)
- 80% (22.8 reps for 3648 lb) — 50% (74.6 reps for 7460 lb)
- 80% (26.9 reps for 4304 lb) — 50% (87.4 reps for 8740 lb)
When the lifter went from a one to two-minute rest interval, they gained 28 and 27 percent on volume and tonnage at the 80 and 50 percent intensities, respectively. When they went from a two to three-minute rest interval, each improved by another 18 and 17 percent, respectively. When the lifters took three-minute rest intervals instead of one, they increased their volume and tonnage 51 percent at the 80%1RM intensity and 48 percent at the 50%1RM intensity. This is far from trivial. Even if we are under the impression that shorter rest intervals are better for hypertrophy because of The Pump™, we cannot ignore the discrepancy between the total volume/work we can accumulate with longer rest intervals versus the short intervals. The Reader can re-read the first segment on volume if he forgot the importance.
In this meta-analysis Holy Grail, Henselmans and Schoenfeld looked at every study that “examined the relationship between inter-set rest intervals and muscle hypertrophy or a mechanism underlying or mediating this relationship” in order to decipher whether there is merit in implementing short rest intervals, the ones usually promoted as superior for hypertrophic G A I N S, over longer rest intervals, the ones usually promoted as superior for strength G A I N S. In short, they concluded, “to date, no study has demonstrated greater muscle hypertrophy using shorter compared with longer rest intervals.” I’ll go out on a limb and assume the Reader may need more convincing on this topic. I will quote (and add emphasis where I please) their efficient use of the English language from the abstract:
“Rest intervals less than 1 minute can result in acute increases in serum growth hormone levels and these rest intervals also decrease the serum testosterone to cortisol ratio. Long-term adaptations may abate the postexercise endocrinological response and the relationship between the transient change in hormonal production and chronic muscular hypertrophy is highly contentious and appears to be weak. The relationship between the rest interval-mediated effect on immune system response, muscle damage, metabolic stress, or energy production capacity and muscle hypertrophy is still ambiguous and largely theoretical. In conclusion, the literature does not support the hypothesis that training for muscle hypertrophy requires shorter rest intervals than training for strength development or that predetermined rest intervals are preferable to auto-regulated rest periods in this regard.” – Henselmans & Schoenfeld
They add in the conclusion, “previous recommendations to employ 0.5- to 1-min rest intervals in resistance training programs designed to maximally stimulate muscle hypertrophy mediated by an elevation in post-exercise serum growth hormone levels have become scientifically untenable.” Bring on the controversy. I live for this.
“Longitudinal studies that directly measured hypertrophy in groups with various rest intervals found either no differences between groups or, in the study by Buresh et al., a higher increase in muscle girth in the group using 2.5-min rest intervals than in the group using 1-min rest intervals.” The Reader already knows about this study, as I covered it in a bit more detail above. When that study is understood in its entirety, it’s clear that trained subjects would not experience those differences in muscle growth.
A message to all of the fitness experts who say ‘try THIS rest interval for UNREAL TESTOSTERONE production!’: “the decrease in testosterone to cortisol ratio associated with rest intervals shorter than 2 min may be detrimental to muscle growth, but this remains a theoretical concern in the absence of empirical support. Other hormone levels seem to generally be unaffected by the manipulation of inter-set rest periods.” Essentially, there is absolutely no evidence that shorter rest intervals provide any significant endocrinological effects.
In regards to the metabolic stress and cell swelling that is associated with shorter rest intervals and The Pump™, “there is currently no direct empirical evidence to support the hypothesis that shortening inter-set rest periods will benefit chronic muscle hypertrophy as a result of increased metabolic stress.” Moreover, “rest interval length does not seem to be associated with markers of muscle damage, with the exception of an increase in individuals with a high serum [creatine kinase] response to resistance training. In these individuals, the extraordinary increase in muscle damage may impair muscle hypertrophy.”
In summation, “more generally, the literature as a whole suggests that rest interval manipulation has minor effects on muscle hypertrophy compared with other training parameters such as work volume, which suffers when inter-set rest is insufficient even in trainees accustomed to this type of training.” Didn’t I say this a couple minutes ago? I wish I weren’t right all the time. Volume is still the most important factor when it comes to hypertrophy. If we want to be muscular, we need to improve our total work capacity, slowly but efficiently. Longer rest intervals give us a much better shot at performing higher volume which skews our training toward higher levels of tonnage over time which will lend itself to a greater work capacity.
With even a modicum of impartiality, it becomes obvious that we should ditch the idea that shorter rest intervals are preferable to longer for hypertrophic training outcomes. Perhaps, PERHAPS, it is possible that the short rest interval dogma is merely tradition that has been handed down through the generations, as the bodybuilding community has historically been, let’s say, forgetful when asked to provide a citation for _____ belief. Given the obvious benefits in strength and accumulated volume and/or tonnage that come from longer rest intervals, why would we not center our training around relatively high-intensity sets with 2+ minutes of rest? Okay, so we need much volume in the 1-12 rep range with rest intervals north of two minutes, with auto-regulation being our best tool, but what does The Literature say about tonnage and its link to hypertrophy? Well, not a lot.
In this study by Schoenfeld et al., high versus moderate loading with equated tonnage was tested in trained men. The groups performed either seven sets of 3RM with a three-minute rest interval or three sets of 10RM with a 90-second rest interval. The former group, more of a powerlifting-style program, saw significant increases in strength over the latter group, as we’ve come to expect, but both groups saw similar increases in muscle thickness (12.6 and 12.7 percent). So, more sets at a higher load with a longer rest interval showed the same results as a lighter load to failure. The researchers controlled it so that tonnage was equal in the workouts. This shows that almost identical hypertrophic effects might be achieved at quite different loads with equalized tonnage, but it’s hard to make any inferences from this study.
In this study, Schoenfeld et al. tested heavy versus moderate loading in trained men without equated tonnage. Two groups were tested; one group (HEAVY, n=10) would perform three sets of two to four reps based on their 3RM for seven exercises three days per week and the other group’s (MODERATE, n=9) only difference was three sets of eight to twelve reps based on their 10RM, full-body was trained each day for HEAVY and MODERATE. Both groups saw increases in muscle thickness, but the results favored the MODERATE group. Strength increases favored the HEAVY group significantly. Muscular endurance increases favored the HEAVY group as well.
The volume for the MODERATE group was upwards of 756 working reps per week against the HEAVY group’s ~252 reps. That is a stark discrepancy and Schoenfeld et al. noted that the tonnage was almost half in the HEAVY group. I think this is a great reinforcement of our volume philosophy. Although the HEAVY group was able to work at higher intensities and gain significantly more strength throughout the study, they simply were not performing enough sets on a weekly basis. Had the HEAVY prescription been five or six sets per exercise instead of three, I think the outcomes would have been quite different, although this is speculation. By the way, if the Reader is seeing this sentence, kudos. I respect you. I think this study hints at the possible importance of volume load, but it certainly reinforces the importance of volume proper.
This study by Mangine et al. tested 29 trained men in order to test high-ish volume versus low volume with high intensity. These men were given strength tests and a two-week preparatory phase prior to being randomly split into a high-volume (VOL, n=14) group that performed four sets of 10-12 reps at ~70% 1RM with one-minute rest intervals or a high-intensity (INT, n=15) group that performed four sets of three to five reps at ~90% 1RM with three-minute rest intervals. What’s surprising about this study is that despite the fact that INT’s tonnage was drastically lower (about half) than VOL’s, they had significantly better hypertrophic responses against the minimal difference in almost all measures. To quote (and add emphasis) them directly:
“The major findings of this study indicated that 8 weeks of high-intensity, low-volume resistance training utilizing long rest intervals stimulated significantly greater 1RM bench press and lean arm mass gains compared to moderate intensity, high-volume program utilizing short rest intervals in resistance-trained men. These results are consistent with previous comparative studies in resistance-trained individuals showing high-intensity programs were more conducive for increasing strength while producing similar magnitude of muscle hypertrophy (Brandenburg and Docherty 2002; Schoenfeld et al. 2014). However, the greater gains in some measures of muscle size observed in INT indicate that high-intensity training may provide a greater stimulus for muscle hypertrophy in trained men.” – Mangine et al.
Contradicting our last study, even if the volume and tonnage are relatively low, similar but possibly favorable hypertrophy gains, and significantly superior strength gains can be made in resistance-trained lifters. To me, the link between tonnage and hypertrophy is tenuous. I will hesitate to claim that tonnage is a factor in predicting hypertrophic training outcomes, as the evidence is not on my side and far from conclusive. It seems there is perhaps a positive correlation, but I think it is merely as a byproduct of volume. The more volume we perform, the higher the tonnage will be, especially if the loads are closer to 1RM. However, we don’t see any predictive characteristics in tonnage.
Now I must come to another sacred cow, frequency. In bodybuilding, the only way to train is with splits. The body is divided into muscle groups and movements are mostly irrelevant. In some programs, a muscle group will be stressed two or more times in a week, but the majority of bodybuilding splits hit one muscle group for many sets and reps once per week. Let us see what the data say.
Frequency (and Responsiveness)
In a large-scale study by Hubal et al., researchers tested isometric maximal voluntary contraction (MVC), dynamic strength (one-repetition maximum (1RM)) of the elbow flexor muscles of each arm, and magnetic resonance imaging (MRI) of the biceps brachii (to determine cross-sectional area (CSA)) after a 12-week progressive dynamic resistance training program of the nondominant arm. They used these metrics to study the responsiveness of the subjects, seeing a range of muscle size changes from -2 to +59% in 585 subjects (342 women and 243 men). Yes, some folks had an extremely poor response to the training and regressed ever-so-slightly. However, it was found that the level of “low-” or “non-responders” was much higher as the frequency of training was lower. As the group was required to do more work in the study, “low-responsiveness” was much less prevalent and “high-responsiveness” was much more common. What does this mean?
Across the board, when some form of a medical/health/fitness intervention is applied to a large sample, we will see a huge variation in response to the applied stress. This is because of the natural variation that humans display. When the stress is equated, as in this study, we see several subjects respond exceedingly well and their hypertrophic results were great, despite the minimal intervention. However, we also see several subjects respond either negatively or with single-digit positive percentages.
As I discussed in my post on athleticism, humans vary greatly and men tend to vary in a wider range than women. We can see this illustrated above. The point, though, is that all human populations vary in their robustness of response to training. Unsurprisingly, we saw the prevalence of non-/low-responders decrease as the training frequency increased. This shows us that even though these subjects have an unfortunate tendency to respond minimally or not at all to a little training, we can improve their responsiveness drastically by increasing how often they train a movement/muscle group.
Frequency is correlated with responsiveness to training, that is an excellent thing to know. Their conclusions (emphasis added by me) on volume, intensity, and tonnage are as follows:
“The amount of load used is a potentially confounding factor when considering RT volume; the evidence seems to show that the use of heavier loads requires performance of a greater number of sets to maximize the growth response, although this does not appear to be the case with lighter loads. For low-loads with higher repetitions, it is evident that higher VL is needed to reach peripheral fatigue and thus induce a sufficient training stimuli. Therefore, it is necessary to emphasize that while training volume is an important variable, ultimately, the interplay between external load and volume will likely determine the adaptive response. On the point of training load, some studies indicate a preferential growth of type I and type II muscle fibers with lowload and high-load training, respectively (25, 32). For the individual whose sole goal is maximize muscular development (e.g. bodybuilder), the findings suggest that both loading schemes should be combined, making this a potentially important variable to consider in addition to training volume. On the other hand, those whose goal is to maximize strength should stick primarily with heavier loads as this type of training has greater transfer to the ability to produce force.” – Schoenfeld & Grgic
Essentially, there needs to be an interplay between the intensity and volume if one is to optimize their training. Moreover, it is recommended that cycles of higher load and lower loads be utilized if one wants to maximize hypertrophy, as type I and type II fibers will be recruited in our intensity’s proximity to 1RM, as we discussed earlier. If low-loads are used, one must hit a high amount of tonnage to reach an overload event that will cause an adaptation. A set with 20 or more reps is what we in The Biz call “masturbation”. If the Reader is performing 20+ reps in the gym, this will be played through the speakers on repeat. Masturbation is strictly forbidden in the weight room. The intensity necessary in order to perform that many reps is absurdly low and it’s likely that after one becomes well-trained, such low intensities will not disrupt homeostasis unless immense tonnage is accumulated. Lastly, if one is predominantly interested in strength, it doesn’t seem to be optimal to drop the load below 68-72%1RM at any point in training unless they want to have fun and get The Pump™.
An excellent study done by Zaroni et al. tested whether bodybuilding-style splits or full-body workouts were more beneficial for strength and hypertrophy in trained men, i.e. how does frequency influence G A I N S? The first group (TOTAL, n=9) trained their whole body with an exercise for each muscle group five days per week. Their program was this:
The second group (SPLIT, n=9) trained in a prototypical bodybuilder fashion, training with a boatload of volume for one muscle group per day. Their program was this:
The Reader will have problems with both programs and will feel the desire to nitpick, but remember that laboratory programs have to be very uniform and specific so that they can eliminate as many variables as possible. For the most part, these are pretty solid training programs and roughly represent each philosophy quite well.
The results were close to what I would expect, although no significant increases in strength were found in one group over the other. The 1RM bench, squat, and row improvements favored the TOTAL group but the differences were not significant. However, the hypertrophy response was significantly greater in the TOTAL group. I believe this stems, in part, from the difference in Total Load Lifted, which favored the TOTAL group over SPLIT.
The weekly difference in tonnage was insignificant while favoring the TOTAL group, but over time this created a significant difference in training tonnage. This is because the TOTAL prescription allowed 24 hours of rest between exercises for each muscle group, which resulted in higher volume and tonnage per exercise. We know that tonnage is not predictive of hypertrophy, but it seems to be a byproduct of the programming that is predictive of hypertrophy. The TOTAL group accumulating more volume and tonnage is not surprising, as it’s obvious to anybody who has done a bodybuilding split that by the third consecutive exercise for a single muscle group there is a substantial amount of peripheral fatigue limiting the load with which a lifter can work on the later sets.
Is this a perfect study? Nope, but one will never find a perfect study. What we have, though, is a dandy, highly unique experiment that illustrates an important principle: frequency is better than annihilation. If we can hit a muscle group with 15 working sets over a week and lift heavier loads during those sets than we would be able to if we were to execute all of those sets in one day, we will have better results. This is obvious when we take the time to think it through.
Recall the story of Milo of Croton. He was the great Olympian wrestler who carried a calf over his shoulders every day, and as it grew so did his strength. Eventually, he was able to carry an adult bull on his shoulders over a remarkable distance (in one the most badass death stories of all time, he got lodged inside of a tree while trying to rip it in half and was eaten by wolves). It does not matter that this story is almost certainly apocryphal. As all mythological stories do, it illustrates a point that is essential to our nature and not bound by historical truth. He would not have grown in the same way if he carried the bull seven times every Monday as he did carrying the bull once every day.
Anyone who has executed a bodybuilding split for an extended period of time knows that after a workout the muscle group that was trained is quite sore, sometimes totally debilitated, for 24-72 hours. The golden retriever who created this bodybuilding program vindicates this soreness with the rationalization that there will be plenty of time to recover, often a whole week. However, even with this insane workload for one day, it’s likely that the lifter is fully recovered after 48 to 72 hours following the workout (and this timeframe shrinks as one becomes more trained due to the Repeated Bout Effect). What then for the next 96 hours? Detraining. It’s likely that the lifter will fall back approximately to the homeostatic range where he lived prior to the previous workout with only a minimal gain in strength and/or hypertrophy if any. It is the opinion of The Writer that the lifter should rarely be sore. If the lifter is sore regularly, the programming is not appropriate for the lifter’s training history, level of stress, nutrition, rest, shoe size, schedule, et cetera.
The last study didn’t show significant strength gains in the TOTAL group, but I chalk that up to the rep range being moderate instead of low to moderate. This is not a big deal, as the researchers were wise to make all the lifting equal save the schedule. Ideally, a similar study would include a third cohort lifting heavy while accumulating similar volume, although we don’t need any more evidence that lifting makes us strong.
Brevity Is the Soul of Wit
1) VOLUME – the most respected man in all of the land. We need to befriend him.
2) FREQUENCY – we are undertrained, not overtrained. Hit it hard and often.
3) INTENSITY – we must not fly too close to the sun, but we still have to fly.
Yin and Yang – High and Low
In Schoenfeld & Grgic’s work, it is argued that training is optimized and healthiest when phases are used to introduce higher and lower cycles of volume. One would benefit greatly from doing a strength phase with moderate volume (I am arbitrarily calling 6-12 working sets per movement/muscle group per week moderate volume) since it improves our ability to produce force more than any other style of training while still allowing us hypertrophic benefits, then slowly expand volume throughout the following weeks and monitor intensity closely to phase out of the strength focus into a cycle of hypertrophy focus. This would achieve a few things.
- Give us a scheduled break from an insane level of volume, upwards of 20 working sets per movement/muscle group per week, as this brings on a tidal wave of central peripheral fatigue after several consecutive weeks.
- Allow us to get stronger, which will make our working sets in the volume phase heavier than they were in the previous volume phase. In other words, if a level of volume at a certain intensity needs to be reached for optimized hypertrophy, it would follow that a lifter who can perform that work with a heavier load (more tonnage) is probably bigger and stronger than the one who has to use a lighter load (less tonnage) at the same intensity.
- Give our training some welcomed variety, making it more fun (aiding adherence and overall disposition) and utilizing all the muscle fiber types we have.
If we do not change up the training, we will be in serious trouble. I believe volume can drop as low as six working sets per movement per week, but any lower would probably be a bit of detraining. This would only be for a deloading phase. After that, a minimum of 8-10 working sets per movement per week seems to be absolutely essential for hypertrophy while we slowly titrate up to 15-20 sets. Tolerating this amount of work is going to be largely dependent on the individual, although phasing in and out of higher volume is compulsory for all lifters. If a lifter is training with extremely high volume for an extended period of time, say, 6+ consecutive weeks:
- He is using all the steroids available and has such a remarkable work capacity that he can do this without dying.
- The load is so low that this level of volume becomes a recoverable stimulus after a few weeks of adaptation. However, at this level of intensity, our bodies can accommodate to this in such a way that we will no longer see it as a viable overload event, i.e. we will not become Milo of Croton.
As we saw in the Hubal et al. study, the second group using loads below 60%1RM needs to accumulate a ridiculous amount of tonnage to get anywhere near an overload event. This is a lot of wasted time, the one resource with which we cannot be complacent, as our heart beats for a blip and then we disintegrate into the ether from which we came.
Additionally, there is a massive difference in individual responsiveness to training that cannot be overcome by a particular program or template. Some individuals will seemingly not respond at all to a certain exercise prescription while another individual might glance at the doors of a gym on the drive home and gain an inch on his arms. This is not fair, but it is our Reality. The way we overcome this unfairness is frequency. Strength training, and particularly bodybuilding, is a game of work capacity. We best improve our ability to do work with the following three tactics.
Volume is all-powerful. In order to achieve the look of the Farnese Hercules, we must imagine him performing his 12 sets of labor. Volume needs to be understood and calculated so that we know what we have been doing previously, where we are now, and where we need to go with our programming in the future. The thought process on how to approach this is best understood through the Grey Book, Practical Programming for Strength Training. A good primer is my post on Intermittent Programming Disease (IPD).
Frequency is the second ally of the man yearning for aesthetics. No story illustrates its importance better than Milo’s. As we become more trained, we are going to need to hit movements/muscle groups more often. That is just a consequence of Becoming a Beast. I already explained why it is counterproductive to hit all of our working sets per movement/muscle group in one workout, e.g. strict bodybuilding splits. Look to full-body workouts three or four days per week or an upper/lower split four days per week. I think the 4-Day Texas Method splits from the Grey Book are an excellent place to start. Those versatile paradigms seem to be the best schedules for the Un-Novice Lifter™.
Intensity/Load is always going to be a factor. It is best to keep the story of Icarus in one’s mind when programming intensity. Flying too close to the sun, 95-100%1RM, is bound to cause some crashing and burning, but so will flying too close to the sea, sub-60%1RM. We are aware that the homo sapiens’ relationship with the world around him is based on force production, so it is better that he is strong rather than weak. Intensity will be highest during a strength phase and will slowly decrease as our volume is ramped up, although we know from The Literature that dipping below 60 percent of our 1RM for high-rep sets is tomfoolery. Never forget that a 20+ rep set is masturbation.
For now, meditate on Herculean Volume, Milo’s Frequency, the Intensity of Icarus, and let the Un-Novice Lifter™ Template from my IPD post act as the first step for turning the science above into programmable training. A Deep Dive into how we should go about programming for maximized hypertrophy will bring at least another 5,000 words, so let me save that for another time.
Most folks checked out somewhere in the middle of this post. They cannot handle this article because they are weak. Physically, mentally, and spiritually. They have not realized their will to power. I can say anything I want down here, I’m all alone. Footloose is the worst movie I’ve ever seen and Jennifer Aniston is starting to show a bit of aging. This is alarming for me because she has been hot longer than I have been alive. Clearly, my death is impending. The Reader does not deserve to absorb this article for free. The above is a compilation of 330+ studies. Send me one hundred dollars. 9524 words.
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